Correction: I'm getting wildly different IP addresses not wildly
different MAC addresses.
On Sat, Feb 8, 2014 at 9:42 AM, Linux Luser linuxlu...@gmail.com wrote:
dhcp-ignore-clid might just work for the long-term. But I ended up
playing around a bit more and I've managed to isolate the part of my config
that I believe triggers the problem. Maybe this can be fixed without a
dhcp-ignore-clid option?
When I set a host's MAC address and IP association in /etc/ethers (with
the read-ethers option on of course) and that same host's IP address to
hostname association in /etc/hosts, I am able to get a consistent IP,
whether or not that same host is using PXE boot, the Debian installer
(where it send the vendor-id as d-i, which shouldn't matter in this case)
or boots to its own image on the drive. It is consistent, that is, until I
implement a trick that I wanted to use so I could whitelist hosts for
PXEboot. That's when it got inconsistent and I would end up with a brand
new IP address for PXE and usually another brand new one when the host boot
into it's own OS. I could only get the IP that I had set in /etc/ethers if
I restarted dnsmasq on the server. Otherwise the host would receive the
same WRONG IP over and over for each renewal.
Here's the config I had BEFORE implementing a PXEboot whitelist:
domain-needed
bogus-priv
log-dhcp
domain=mydomain
local=/mydomain/
server=8.8.8.8
server=8.8.4.4
interface=eth0
except-interface=eth1
expand-hosts
read-ethers
dhcp-range=tag:known,set:controller,10.1.0.1,10.1.255.254,2h
dhcp-range=tag:known,set:device,10.2.0.1,10.2.255.254,2h
dhcp-option=option:router,10.0.0.1
enable-tftp
tftp-root=/tftpboot
dhcp-boot=pxelinux.0
Now, I'll add the lines which allow me to use a directory of files for
dhcp-host commands:
dhcp-vendorclass=pxe,PXEClient
dhcp-ignore=tag:pxe,tag:!install
dhcp-hostsfile=/etc/dnsmasq-hosts.d
Inside of /etc/dnsmasq-hosts.d then I can put files that contain lines
like this one:
01:02:03:04:05:06,set:install
... and send a SIGHUP to dnsmasq process. After this, the host with that
MAC address gets the tag install and instead of ignoring PXEboot, dnsmasq
will respond for that host. Wonderful! Problem: now I'm getting wildly
different MAC addresses. It's like dnsmasq is reading the files in
/etc/dnsmasq-hosts.d and ignoring the /etc/ethers file. Is this expected
behavior? A bug? I know that specifying a DIRECTORY instead of a file for
the dhcp-hostsfile is kind of a new feature. (For my purposes, I'd prefer a
directory because it's possible that several processes might want to write
files at the same time. It's easy to avoid concurrency problems by putting
files with unique names in a directory (named after MAC or hostname or
UUIDs, etc).)
FYI, I'm using version 2.59 (comes with Debian wheezy). Thanks for any
help!
On Fri, Jan 31, 2014 at 1:48 PM, Simon Kelley si...@thekelleys.org.ukwrote:
On 31/01/14 16:25, Linux Luser wrote:
dhcp-ignore-names is concerned about the hostname, correct? I am
interested in the client identifier option sent in the DHCPREQUEST.
Ignoring this field would break RCF2131 (and probably some people's
networks!) but in my particular case, it may spare me some problems.
I understand, I'm proposing a new option, dhcp-ignore-clid, analogous to
the existing dhcp-ignore-names.
Maybe if I could selectively revoke leases, that would work. Could I do
this? I'm sure that dnsmasq keeps an internal cache, so that would have
to be flushed for a particular lease.
There is a utility in contrib/wrt in the source distribution, and a
binary in the Debiann package of dnsmasq, for releasing a specific lease
from the command-line.
On Jan 30, 2014 2:08 AM, Simon Kelley si...@thekelleys.org.uk
mailto:si...@thekelleys.org.uk wrote:
On 29/01/14 18:04, Linux Luser wrote:
We have a pretty tightly-controlled private network environment
which
we've configured to have a 1-to-1-to-1 relationship between
client MAC
address, hostnames and IP addresses. Apart from guest IP
ranges, we
have control over when clients get added to the network. Thus,
we can
detect duplicate MAC addresses before it becomes an issue.
In this setup, we can't need or want to use the client
identifier
option of DHCP. In fact, it becomes a problem when we start doing
PXELinux installs, where a different client id gets sets during
a remote
install session, then when the install is complete and the new
OS boots
up, it gets a different IP address (because dnsmasq still knows
about
the lease it gave that same machine only 10 minutes ago!).
To get rid of this issue, we now supply a dhcp-host option to
dnsmasq
each time we want to do a remote reinstall. The option looks
something
like this:
